Honeycomb structure

Abstract

A conductive honeycomb structure includes: a pillar honeycomb structure portion including an outer peripheral side wall and partition walls, each of the partition walls extending through the pillar honeycomb structure from a first end face to a second end face to define a plurality of cells forming a through channel of a first fluid; a pair of electrode portions disposed in contact with an outer surface of the outer peripheral side wall across a central axis of the honeycomb structure portion; and a pair of terminal connecting portions formed on the outer peripheral side wall, each of the terminal connecting portions being at least partially covered with each of the electrode portions. Each of the electrode portions includes band-shape first, second and third electrode layers each having a predetermined electrical resistance.

What is claimed is: 
     
       1. A conductive honeycomb structure, comprising:
 a pillar shape honeycomb structure portion having:
 an outer peripheral side wall; and 
 partition walls extending through the pillar shape honeycomb structure from a first end face to a second end face to define a plurality of cells forming a through channel; 
 
 a pair of electrode portions disposed on an outer surface of the outer peripheral side wall, and one electrode portion in the pair of electrode portions being disposed on a side opposite to the other electrode portion across a central axis of the honeycomb structure portion; and 
 a pair of terminal connecting portions disposed on the outer peripheral side wall; 
 wherein each of the pair of electrode portions comprises a first electrode layer, a second electrode layer, and a third electrode layer; 
 each of the first, second and third electrode layers is shaped in a form of a band extending in a flow path direction of the cells, 
 each of the first, second and third electrode layers is disposed on the outer surface of the outer peripheral side wall, 
 the second electrode layer, the first electrode layer, and the third electrode layer are connected in series in a circumferential direction of the outer peripheral side wall in this order, 
 at least a part of the pair of terminal connecting portions is covered with the first electrode layer; 
 each of the pair of electrode portions has an electrical resistivity lower than the honeycomb structure portion; and 
 the conductive honeycomb structure satisfies;
     R   1   /R   2 ≤0.2 and  R   1   /R   3 ≤0.2,
 
 
 
       in the above formulas, in each of the electrode portions,
 R 1  is an electrical resistance between the terminal connecting portion and a surface point of the first electrode layer farthest from the terminal connecting portion in the flow path direction of the cells; 
 R 2  is an electrical resistance between the terminal connecting portion and a surface point of the second electrode layer farthest from the terminal connecting portion in the circumferential direction of the outer peripheral side wall; and 
 R 3  is an electrical resistance between the terminal connecting portion and a surface point of the third electrode layer farthest from the terminal connecting portion in the circumferential direction of the outer peripheral side wall. 
 
     
     
       2. The conductive honeycomb structure according to  claim 1 , wherein the conductive honeycomb structure satisfies;
   ρ 1 /ρ 2 ≤0.5 and ρ 1 /ρ 3 ≤0.5,
 
 
       in which the above formulas,
 ρ 1  is an electrical resistivity of the first electrode layer; ρ 2  is an electrical resistivity of the second electrode layer; and ρ 3  is an electrical resistivity of the third electrode layer. 
 
     
     
       3. The conductive honeycomb structure according to  claim 1 , wherein the conductive honeycomb structure satisfies 0.8≤ρ 2 /ρ 3 ≤1.2. 
     
     
       4. The conductive honeycomb structure according to  claim 1 , wherein each of the pair of electrode portions is disposed on line symmetry with a straight line connecting respective centers in the circumferential direction of the pair of electrode portions as an axis of symmetry, in any of cross sections orthogonal to the flow path direction of the cells. 
     
     
       5. The conductive honeycomb structure according to  claim 1 , wherein the honeycomb structure portion has an electrical resistivity in a range of from 0.001 Ω·cm to 1 Ω·cm, and
 each of the pair of electrode portions has an electrical resistivity in a range of from 0.0001 Ω·cm to 0.1 Ω·cm. 
 
     
     
       6. The conductive honeycomb structure according to  claim 1 , wherein
 the outer peripheral side wall comprises a pair of protruding portions extending in the flow path direction of the cells, and 
 one protruding portion in the pair of protruding portions is disposed on a side opposite to the other protruding portion across a central axis of the honeycomb structure portion, and 
 wherein each of the pair of terminal connecting portions is disposed at a position where each of the pair of protruding portions is formed. 
 
     
     
       7. A conductive honeycomb structure, comprising:
 a pillar shape honeycomb structure portion having:
 an outer peripheral side wall; and 
 partition walls extending through the pillar shape honeycomb structure from a first end face to a second end face to define a plurality of cells forming a through channel; 
 
 a pair of electrode portions disposed on an outer surface of the outer peripheral side wall, and one electrode portion in the pair of electrode portions being disposed on a side opposite to the other electrode portion across a central axis of the honeycomb structure portion; and 
 a pair of terminal connecting portions disposed on the outer peripheral side wall; 
 wherein each of the pair of electrode portions comprises: 
 a band-shape first electrode layer extending from one end, passing through the terminal connecting portion so as to cover at least a part of the terminal connecting portion, to the other end, in a circumferential direction of the outer peripheral side wall, while being in contact with the outer surface of the outer peripheral side wall; 
 a band-shape second electrode layer connected to one end of the first electrode layer and extending from the one end in a flow path direction of the cells while being in contact with the outer surface of the outer peripheral side wall; and 
 a band-shape third electrode layer connected to the other end of the first electrode layer and extending from the other end in the flow path direction of the cells while being in contact with the outer surface of the outer peripheral sidewall; 
 each of the pair of electrode portions has an electrical resistivity lower than the honeycomb structure portion; 
 at least a part of the pair of terminal connecting portions is covered with the first band-shape electrode layer; and 
 wherein the conductive honeycomb structure satisfies;
     R   2   /R   12 ≤0.2 and  R   3   /R   13 ≤0.2,
 
 
 
       in the above formulas,
 in each of the electrode portions, R 12  is an electrical resistance between the terminal connecting portion and a surface point A 1  of the first band-shape electrode layer farthest in the circumferential direction of the outer peripheral side wall from the terminal connecting portion toward the second band-shape electrode layer; 
 R 2  is an electrical resistance between a surface point A 2  of the band-shape second electrode layer closest to the terminal connecting portion in the circumferential direction of the outer circumference side wall and a surface point A 3  of the band-shape second electrode layer farthest from the surface point A 2  in the flow path direction of the cells; 
 R 13  is an electrical resistance between the terminal connecting portion and a surface point B 1  of the first band-shape electrode layer farthest in the circumferential direction of the outer peripheral side wall from the terminal connecting portion toward the third band-shape electrode layer; and 
 R 3  is an electrical resistance between a surface point B 2  of the third band-shape electrode layer closest to the terminal connecting portion in the circumferential direction of the outer circumference side wall and a surface point B 3  of the third band-shape electrode layer farthest from the surface point B 2  in the flow path direction of the cells. 
 
     
     
       8. The conductive honeycomb structure according to  claim 7 , wherein the conductive honeycomb structure satisfies;
   ρ 2 /ρ 1 ≤0.5 and ρ 3 /ρ 1 ≤0.5,
 
 
       in the above formulas,
 ρ 1  is an electrical resistivity of the first band-shape electrode layer; ρ 2  is an electrical resistivity of the second band-shape electrode layer; and ρ 3  is an electrical resistivity of the third band-shape electrode layer. 
 
     
     
       9. The conductive honeycomb structure according to  claim 7 , wherein the conductive honeycomb structure satisfies 0.8≤ρ 2 /ρ 3 ≤1.2. 
     
     
       10. The conductive honeycomb structure according to  claim 7 , wherein each of the pair of electrode portions is disposed on line symmetry with a straight line connecting respective centers in the circumferential direction of the pair of electrode portions as an axis of symmetry, in any of cross sections orthogonal to the flow path direction of the cells. 
     
     
       11. The conductive honeycomb structure according to  claim 7 , wherein the honeycomb structure portion has an electrical resistivity in a range of from 0.001 Ω·cm to 1 Ω·cm, and
 each of pair of the electrode portions has an electrical resistivity in a range of from 0.0001 Ω·cm to 0.1 Ω·cm. 
 
     
     
       12. The conductive honeycomb structure according to  claim 7 , wherein
 the outer peripheral side wall comprises a pair of protruding portions extending in the flow path direction of the cells, and 
 one protruding portion in the pair of protruding portions is disposed on a side opposite to the other protruding portion across a central axis of the honeycomb structure portion, and 
 wherein each of pair of the terminal connecting portions disposed at a position where each of the pair of protruding portions is formed.